The present invention relates to a continuous flow type heating apparatus which can instantly heat up liquid continuously flowing in a pipe, and more particularly, a continuous flow type heating apparatus which instantly heats up fluid using microwave.
Among the methods to supply and heat up water continuously flowing in a pipe to a desired temperature like an instantaneous boiler, there are methods using gas or electricity as a heat source.
The gas using method employs a gas burner at the bottom of a housing, a heat exchange pipe in which water flows is configured such that the path of the pipe in the housing becomes relatively long, for example, in a spiral shape. Heating is carried out by heating the pipe from outside with the gas burner.
However, since it takes long to get the water inside hot by heating the pipe, the method is not always good in terms of heat efficiency. Since the method involves a combustion process, air is polluted. There is some fear of monoxide poisoning created by the combustion and of gas poisoning created by a black out of fire. Further, since the method requires a long pipe path in order to achieve high heating temperature, an apparatus itself is difficult to be designed small.
On the other hand, although the electrical method does not generate the problems of the air pollution, the gas poisoning, and a need for air exchange, involved in the gas method, the heater to heat up flowing water takes long for a temperature rise, requires a high running cost, and has a technological difficulty in supplying water at a constant temperature because the temperature of hot water decreases when the hot water being used.
Concerning the problems in the gas and the electricity, an induction heating method which instantaneously heats up fluid using magnetron, in the continuous flow type heating apparatus like the instantaneous boiler, is proposed.
For example, according to Japanese Utility Model Application Publication (KOKAI) S63-52296, there is disclosed a continuous liquid heating apparatus in which: a heating part made by installing one or multi-numbers of heating pipes in parallel, is located in a microwave irradiation chamber related to the microwave generator; the pipe is made of a metal pipe covered by exterior parts in which ferrite is mixed; in the heating part, a liquid-flow-in pipe and liquid-flow-out pipe are connected; the liquid is continuously heated from inside using microwave; and the ferrite having high microwave absorption efficiency is utilized to continuously heat up from outside during the heating.
In Japanese Utility Model Application Publication (KOKAI) S63-194251, is disclosed a water heater which comprises a chamber surrounded by walls of insulating material which cuts microwave, a radiation part which radiates microwave into the chamber, and water supply path configured such that the path goes through a microwave irradiation region in the chamber and can continuously supply hot water of necessary amount.
Further, in Japanese Utility Model Application Publication (KOKAI) H01-88345, is disclosed an instantaneous boiler comprising a microwave generator, partition which forms a second chamber containing fluid introduced from outside, a pipe which goes through the partition and a first chamber of the boiler, and is formed such that the fluid flowing inside is heated by the microwave oscillated towards inside of the boiler from the microwave generator.
On the other hand, in Japanese Patent Application Publication (KOKAI) S63-65251, is disclosed a liquid heating method which employs a microwave generator equipped with a microwave oscillating part in a shield case, and a pipe made of fluoric resin set in the shield case facing to said microwave oscillating part to efficiently heat up fluid flowing in the pipe by the microwave. Especially in the publication, it is described that the microwave generator comprises a power supply circuit supplied with commercial AC100V and oscillates microwave at 2450 MHz by receiving high voltage from a high voltage generator circuit generating a high voltage above several KV based on the voltage from the power supply.
In Japanese Patent Application Publication (KOKAI) H01-102242, is disclosed a water heater which can continuously supply hot water of a necessary amount by having a heating element made of microwave resistant material around the outer surface of a water path irradiated by a microwave.
In Japanese Patent Application Publication (KOKAI) H05-248700, is disclosed a boiler which controls a water temperature by changing the output of a microwave oscillator and the water flow when the microwave oscillated from a microwave oscillator is irradiated to the water in a pipe, a container and a bath in order to boil the water.
Furthermore, in Japanese Patent Application Publication (KOKAI) H05-288403, is proposed an electrical water heater comprising a water in gate and a water-out gate having a microwave absorber in mesh shape in a microwave applicator to irradiate microwave to the water flowing in the microwave absorber,.
Any of the electrical water heater and the instantaneous boiler described in said each publication has a common technological idea that microwave is irradiated to the liquid temporarily stored or the fluid continuously flowing, especially water, in order to heat and boil the fluid by the friction heat between water molecules. However, according to the research carried out by the inventors of the present invention, there has not been a fact that any instantaneous boilers using microwave for domestic use, have been sold or employed.
After a dedicated study of the continuous flow type heating apparatus using microwave described in the publications, the inventors of the present invention have reached to a conclusion that the instantaneous boiler and water heater have not come to practical use because even the irradiation of the microwave could not have achieved the sufficiently hot water.
That is, the diameter of the pipe set in the apparatus needs to be large in order to supply necessary amount of hot water in practical use, but sufficient heating can not be done because the pipe of larger diameter has a larger amount of the fluid flowing in the pipe and flow rate.
Higher heating temperature requires larger microwave irradiator with higher heating capability but there are many problems to solve that a larger apparatus occupies installation space, and the voltage of general domestic power supply (A.C.100V) can not be used, and a noise problem on operation is concerned, and leakages of microwave (electric wave leakage) is likely to occur, and the running cost largely increases.
Concerning such problems to solve, the inventors of the present invention have discovered as a result of further study that the microwave irradiated to water osmoses into the water, is absorbed and converted to heat, and then attenuates. As the microwave goes inward of water, it attenuates more to have insignificant contribution to water heating.
That is, the inventors have found that the power half reduction depth of the depth down to which the microwave can heat water, in other words, the depth where the microwave power density becomes xc2xd is about 10 mm, and in the case of flowing water, the power half reduction depth decreases down to ⅓. Based on this result, the present invention has been established.
The objective of the present invention seeks to provide a continuous flow type heating apparatus which heats up water flowing in a pipe by microwave and can continuously supply hot water of the amount and the temperature practically usable.
Another objective of the present invention is to provide a continuous flow type heating apparatus which can raise water temperature effectively with the length of the pipe in which fluid flows as short as possible.
Further objective of the present invention is to provide a continuous flow type heating apparatus which can reduce the consumed power by pre-heating the temperature of the flowing water by the effective use of the heat generated by the microwave oscillator which irradiates microwave.
Further objective of the present invention is to provide a continuous flow-type heating apparatus which employs a microwave generator of a water-cooling type and is completely sealed as a whole and therefore has no noise generation, does not require a particular installation location, prevents the dust from coming in the interior of the apparatus, has no adhesion of the dust to the interior of the condenser, transformer, and magnetron, and prevents the electric leakage caused by the dust.
To achieve the objectives, an invention described in claim 1 is directed to a continuous flow type heating apparatus which is characterized in that microwave irradiation parts are located at the positions facing to each other with a water supply pipe as a center in-between, fluid flowing in the water supply pipe is heated by half portions in the irradiation of microwave from an irradiation part.
An invention described in claim 2 is directed to a continuous flow type heating apparatus which is characterized in that:
a pair of microwave irradiation parts for which slits are formed at a desired interval along longer axis, are set facing to each other; and
a water supply pipe is set at a central part between the irradiation parts; and
a fluid flowing in the water supply pipe is heated by half portions with the irradiation of microwave from the slit.
Further, an invention described in claim 3 is directed to a continuous flow type heating apparatus which is characterized in that:
an opened part with a desired width is formed on an upper surface on one side of a horizontally prolonged empty box made of metallic material, to become a microwave emitting port;
the empty box is divided into two with a vertical partition except for an upper and lower part of the emitting port;
resultant one sectioned space is horizontally divided into three with two of upper and lower partition to which slits are set at a desired interval, orthogonal to the longer axis;
a space formed on the upper partition is a first irradiation part;
a space formed under the lower partition and connected to a space on another side, is a second irradiation part;
a water supply pipe is set at a central part of a space formed between said two of the upper and lower partitions; microwave from a microwave oscillator set on the empty box is emitted into the empty box from the emitting port; and microwave emitted from the slits of said each irradiation part, is irradiated to the upper and lower part of the water supply pipe.